1. Field of the Invention
This invention relates to the chain boards of a metal filings conveyer.
2. Description of the Prior Art
Generally, mechanical processing machinery is installed with a metal filings conveyer for receiving metal filings produced in the course of processing, and transporting the metal filings to a fixed point to be collected. A conventional metal filings conveyer, as shown in FIGS. 1 and 2, includes a plurality of chain boards 1 arranged in parallel, and each chain board 1 is formed with a rectangular base plate 2 having two short sides respectively compressed and bent inward to make up a vertical side plate 3 having a central line (b) that is perpendicular to the lengthwise axis (a) of the base plate 2 to divide the side plate 3 into a first half portion 4 and a second half portion 5, and the second half portion 5 is retracted inward along the lengthwise axis (a) of base plate 2 to form a vertical step with the first half portion 4 of the side plate 3 so that the side plates 3 of two adjacent chain boards 1 can be overlapped on each other. Further, two broadsides of the base plate 2 are respectively disposed along the lengthwise axis (a) with a plurality of pivotal tubes 6 arranged in stagger and at least one pivotal tube 6 abuts upon the second half portion 5 of one of the two side plates 3. In addition, the conventional metal filings conveyer is provided with a plurality of pivotal rods 7 to be respectively inserted in the pivotal tubes 6 at adjacent sides of every two chain boards 1 for connecting the chain boards 1 together to make up a metal filings conveyer.
In order to have the chain boards 1 connected together closely, the series connection length (c) of the pivotal tubes 6 of every two adjacent chain boards 1 must be equal to the distance (d) between two first half portions 4 of the chain board 1, but in this case the length of the pivotal tube 6 abutting upon the second half portion 5 will exceed the bending line (e) of the side plate 3, as shown in FIG. 3, likely to produce interference when the chain board 1 is being integrally formed. In view of the situation, a way of solving the problem of interference is to have the pivotal tube 6, which abuts against the second half portion 5, cut with a skew notch 8 to form a space between this pivotal tube 6 and the side plate 3 to avoid producing interference when the chain board 1 is shaped integrally. However, after the chain boards 1 are combined together to make up a metal filings conveyer, gaps are apt to appear when the metal filings conveyer is operated, and metal filings are likely to drop into the skew notches 8 when the metal filings are received and transported by the metal filings conveyer, resulting in wear and breakage between the chain boards 1 and seriously affecting durability of the metal filings conveyer.